1. Technical Field
The present invention relates to the devices used to measure and dispense a fluent material, and more particularly to an accurate measure that can be achieved quickly and safely.
2. Description of the Art
The use of conventional measurement containers or vessels often results in inaccuracies due to movement of the container and the lack of human dexterity. Containers having a scale marked on their sides rely on a line of sight and the alignment of this line of sight with the top surface of the material being measured. Safety and waste is a problem for containers which must be filled to their top edge. Some laboratory chemicals are very toxic and spillage is also very costly. Speed in accurately obtaining a precise volume of a fluent material is difficult to achieve. Generally speaking, the greater the desired accuracy the longer it takes to achieve it.
A critical and essential factor in the precise measurement of a fluent material is the ability to control the level of the top free surface of the material. Two patents that provide a means to control the surface level are U.S. Pat. Nos. 3,924,472 and 4,283,951. These patents control the top surface of a liquid and a granular material respectively.
The device of U.S. Pat. No. 3,924,472 has a fastening means to attach the container on a wall with a mounting bracket such that the errors in the line of site to the graduated scale are reduced to provide a more accurate measurement. This patent describes a solution to the problem where spillage of the ingredients occurs on numerous occasions as a result of improper holding or movement of the measuring device.
The top surface of a granular material in the dispensing apparatus of U.S. Pat. No. 4,283,951 is controlled to also affect accurate measuring and dispensing of a precise volume. A spring loaded leveler member moves over the top surface to fill voids and remove extra material to achieve a smooth flat top surface of the material. Any excess material is removed in a manner such that it does not remain on or in the apparatus.
Another desirable feature in the precise measurement of a fluent material is the control or elimination of spillage. This problem was discussed in U.S. Pat. No. 3,924,472 as described above and is further disclosed in U.S. Pat. Nos. 2,592,192 and 3,527,270. The patent of U.S. Pat. No. 2,592,192 is for a spoon to measure and administer prescribed doses and the liquid measurer of U.S. Pat. No. 3,527,270 is a cup that has a dish and a saucer to safely receive the contents of the cup.
The spoon of U.S. Pat. No. 2,592,192 is designed to teach a child to use it without spilling the contents. A partial cover has the contour of the bowl of the spoon and forms a cup. Graduations on the cup denote volumetric measures to facilitate correct measurement of liquids. The uncovered part of the bowl of the spoon forms a scoop readily accessible to the user's mouth.
The tipping cup of U.S. Pat. No. 3,527,270 achieves control of spillage in a different means. When the cup becomes full it looses it s balance and empties. Safety is provided by a mounting dish having an opening in the bottom. The liquid passes through the opening and is safely contained in the saucer below the dish. The cup has a brim portion that is lowered below the level of the liquid when the cup is tipped.
A device well known for controlling the elevation of a flowing liquid is the weir. The weir of U.S. Pat. No. 4,467,645 is used to control and measure the amount of water flowing in an open channel by limiting the weir crest across the top of the weir. The weir can also be a notch. The weir concept was also used to control and measure flow rate in U.S. Pat. Nos. 2,018,538 and 4,131,016.
U.S. Pat. No. 2,018,538 discloses an orifice of given diameter for controlling a flow rate into a tank that overflows to maintain a constant level and pressure in the tank. The top edge of the tank operates as a weir having a weir crest during liquid flow. In U.S. Pat. No. 4,131,016, a tubular collection container with an opening at it's upper end is spaced above a lower receptacle wall. The height of the upper end above the lower wall provides a discrete indication of the discharge peak flow rate measured by the device.
A precision measuring device or vessel for accurately measuring large volumes of liquid is disclosed in U.S. Pat. No. 4,033,190. A predetermined overflow level is defined by the position of a tube in the side of the vessel connected through a hole. The tube is connected to an overflow saver vessel for catching and saving any liquid above the desired liquid level. This overflow liquid can be discharged back into the measuring vessel through a second tubing by opening a valve. The primary vessel is emptied through a bottom valve or dumping by rotating about pivot pins. If the primary vessel is dumped by rotation, a valve is necessary in the tube going to the saver vessel, and the top of the saver vessel must be closed.
A feature of any container or vessel to be able to measure multiple volumes of a fluent material is functionally desirable. The spoons of U.S. Pat. No. 2,654,252 are capable of multiple volumes being measured by a single device. Four volumetric portions are formed into a single device. The concave spherical surfaces are capable of measuring a separate volume by filling each to their respective top edge or rim.
The need remains to achieve the quality measurement of large and small volumes of various fluent materials speedily and quickly with a degree of accuracy and safety not now achieved in the industry. This is particularly true for elimination of spillage or wastage to control possible contamination or pollution and reduce the cost of expensive fluent materials. The ability to obtain multiple exactly measured volumes in a single container or vessel also remains to be functionally very desirable. The need to be able to quickly and safely discharge the measured volume is equally important and unfulfilled.